It's not a software issue, the licensee has access to the source code and can modify it in anyway they want, including removing any software-enforced licencing

It's not a software issue, the licensee has access to the source code and can modify it in anyway they want, including removing any software-enforced licencing restrictions. It's the responsibility of the licensee to make sure they are in compliance with the licensing terms (buy enough licenses to cover the number of CPU cores they are running in production), otherwise the copyright holder will sue them. This idea of licencee self-compliance is not an innovative concept, it's how most licensing in large enterprise companies already works (and that's where this license is targeted), the company checks how many copies of the software they are running and pay that much. It's not quite an honer system. Companies conduct regular audits (done by an external company) to prove they have everything licensed correctly.